Evaluation of World Reference Base for Soil Resources and FAO Soil Map of the World using nationwide grid soil data from Denmark

Abstract. Soil classification is a tool for stratifying and generalizing information on soil resources but most systems are tailored to handle only slightly disturbed soil. We tested the applicability of the legend of the FAO-Unesco Soil Map of the World and the new World Reference Base for Soil Resources by classifying at the highest order 831 profiles from a nationwide 7 km grid survey in Denmark, where soils are developed in Quaternary glacial and marine sediments and intensively farmed. Comparison of the variability of pH and % clay +% silt of the master horizons (A, E, B, and C) within and between the major well-drained soil groupings shows that liming, fertilizing and ploughing have produced significantly deeper A-horizons with higher pH, lower % humus and C:N ratios on the two-thirds of the country that is cultivated. ‘Anthropogenic’ mollic and umbric horizons are a common result but the liming causes a random final classification of these surface horizons and, hence, random allocation of the soils in both systems. It separates cultivated soils and their undisturbed equivalents, and results in considerable within-group variation in soil texture. Grouping of cultivated and undisturbed soils, on the other hand, results in wide within-horizon pH ranges for most groups, again compromising the advantage of making useful general statements on the basis of classification. We propose that anthropogenic mollic and umbric horizons should be allowed in any soil group and that ‘anthric properties’ should be used to distinguish between profoundly changed cultivated soils and largely undisturbed soils, hereby constructing a two-tier system within each highest-order soil group. We classified the soils according to this proposal. The results show generally narrower ranges for both pH and % clay +% silt. We evaluated the within-group homogeneity by multivariate analysis of variance of pH, % clay +% silt, % clay, % humus, C:N ratio, exchangeable cations, and CEC. The results (Wilks's Lamda) show a higher degree of group compactness compared to the original FAO and World Reference Base systems.     

沙漠油田地面集输管网腐蚀机理研究

通过对新疆彩南油田集输管网腐蚀现状及腐蚀机理的分析得出，管网腐蚀可归纳为两类：一类是常态性腐蚀；另一类是异态性腐蚀，即由于地形起塞的壁剪切力和与之相伴随的固体颗粒磨蚀，加快了管网腐蚀穿孔速率，导致管道剧烈腐蚀。第一类腐蚀始终存在于整个集输管网当中，而第二类腐蚀常常发生于管道的上坡段。     

Influence of cage size on heart rate and behavior in rhesus monkeys

We studied 6 singly caged adult female rhesus monkeys to determine whether increased cage size had any effect on behavior or heart rate. Two monkeys at a time were placed in cages 40% larger than their standard cage for 1 week on 2 occasions, using a counter-balanced design. Direct behavioral observations were performed 75 minutes/week on each monkey. Heart rate and general activity were monitored 35 hours/week by a telemetry system. Statistically significant differences were not found in aggressive, submissive, abnormal, or self-abusive behavior, nor in time spent in the front half of the cage, duration of grooming, looking at the observer, or stereotyped or nonstereotyped locomotion. Vocalizations increased the first time in the larger cage, but not the second, and decreased upon the second return to the standard cage. Differences with respect to cage size were not found in heart rate or activity level, although there were significant variations at different times of day. We conclude that modest increases in cage size are unlikely to enrich the environment of singly caged laboratory primates.     

Role of EphA4 and EphrinB3 in local neuronal circuits that control walking

Local circuits in the spinal cord that generate locomotion are termed central pattern generators (CPGs). These provide coordinated bilateral control over the normal limb alternation that underlies walking. The molecules that organize the mammalian CPG are unknown. Isolated spinal cords from mice lacking either the EphA4 receptor or its ligand ephrinB3 have lost left-right limb alternation and instead exhibit synchrony. We identified EphA4-positive neurons as an excitatory component of the locomotor CPG. Our study shows that dramatic locomotor changes can occur as a consequence of local genetic rewiring and identifies genes required for the development of normal locomotor behavior.     

基于地形因子的土壤有机碳最优估算模型

基于数字地面模型(Digital Terrain Model,DTM),同时考虑因子组合和分辨率构建土壤有机碳(SOC)最优估算模型。在7 100 km2范围内,选取了71个分辨率和22个地形因子中不多于5个因子的所有可能组合,构造了2 514 820个模型。采样点随机分为两组,6 362个训练样点构造数据挖掘模型,其他2 208个为验证样点。根据模型相关系数r值大小从中选取了不同个数因子组合以及相应分辨率的最优模型,并根据这些模型生成对应的土壤有机碳图。结果表明:单个地形因子模型和栅格大小之间的关系表现出多样化,并不是分辨率越高模型结果越好。单因子模型r值的大小并不能决定其在因子组合模型中的重要性。不同的因子及其组合有其特定的最适分辨率,最佳分辨率范围约为60~150 m。综合数据的存储空间和计算量、模型复杂度、预测精度以及空间表达能力,该地区最优模型由相对坡位、高程、归一化高程及多尺度山谷平坦指数等4个变量组成,对应分辨率为121.6 m。同时与多种克里格空间插值方法生成的土壤有机碳空间分布图进行了对比分析,发现无论几个变量的组合,其空间预测能力均较克里格空间插值方法更能表达SOC的空间变化,预测精度也较高。     

Effect of Days Post-Partum, Breed and Ovum Pick-Up Scheme on Bovine Oocyte Recovery and Embryo Development

The objective of this study was to investigate (i) the effect of two different ovum pick-up (OPU) schemes (once vs twice weekly aspirations) on oocyte recovery rate, quality and subsequent in vitro embryo development, (ii) the influence of days post-partum on oocyte recovery and (iii) possible differences in OPU results from two different herds. In group A, OPU was performed twice weekly in two Holstein Friesian (HF) and three Danish Red and White (DRW) cows from a private herd. In the research herd, two groups of eight HF cows were investigated: group B (OPU once weekly) and group C (OPU twice weekly). The collected oocytes were subsequently submitted to in vitro embryo production. More oocytes were recovered from the private herd when compared with the research herd. In the research herd, the twice weekly scheme aspirated more oocytes than the once weekly scheme. The quality of the retrieved oocytes was significantly different between groups B and C but not between groups A and C, and HF cows yielded higher quality oocytes than DRW cows (p = 0.029). Oocytes from group C showed higher level of embryonic development than group B oocytes. No differences in blastocyst rates were observed between groups A and C. Session affected the number of retrieved oocytes and subsequent developmental rates, with these being lower in the first compared with the last sessions. Finally, there was no significant effect of days post-partum in the number and quality of the retrieved oocytes, likely because of the small group size and high variation between sessions.     

Impact of incubator type on the yield of in vitro produced bovine blastocysts.

Because of suboptimal in vitro production of bovine blastocysts a new incubator model (Mini) was tested against the traditional (Heraeus). The difference between their properties seemed only to be the volume of the incubator space. No difference was noted between the CO2 or the temperature, but the data clearly showed a highly significant increase of the blastocyst rates, 6% versus 51% in the Heraeus and the Mini incubator, respectively, calculated as blastocysts per cleaved embryos. It was concluded that the incubator type or model may be a very important part of the in vitro production of bovine embryos, although we were not able to pin point specific causes for this difference.